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8#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/skbuff.h>
12#include <linux/rtnetlink.h>
13#include <net/netlink.h>
14#include <net/pkt_sched.h>
15#include <net/pkt_cls.h>
16
17#include <linux/tc_act/tc_skbmod.h>
18#include <net/tc_act/tc_skbmod.h>
19
20static unsigned int skbmod_net_id;
21static struct tc_action_ops act_skbmod_ops;
22
23#define MAX_EDIT_LEN ETH_HLEN
24static int tcf_skbmod_act(struct sk_buff *skb, const struct tc_action *a,
25 struct tcf_result *res)
26{
27 struct tcf_skbmod *d = to_skbmod(a);
28 int action;
29 struct tcf_skbmod_params *p;
30 u64 flags;
31 int err;
32
33 tcf_lastuse_update(&d->tcf_tm);
34 bstats_cpu_update(this_cpu_ptr(d->common.cpu_bstats), skb);
35
36
37
38
39
40 err = skb_ensure_writable(skb, MAX_EDIT_LEN);
41 if (unlikely(err))
42 goto drop;
43
44 action = READ_ONCE(d->tcf_action);
45 if (unlikely(action == TC_ACT_SHOT))
46 goto drop;
47
48 p = rcu_dereference_bh(d->skbmod_p);
49 flags = p->flags;
50 if (flags & SKBMOD_F_DMAC)
51 ether_addr_copy(eth_hdr(skb)->h_dest, p->eth_dst);
52 if (flags & SKBMOD_F_SMAC)
53 ether_addr_copy(eth_hdr(skb)->h_source, p->eth_src);
54 if (flags & SKBMOD_F_ETYPE)
55 eth_hdr(skb)->h_proto = p->eth_type;
56
57 if (flags & SKBMOD_F_SWAPMAC) {
58 u16 tmpaddr[ETH_ALEN / 2];
59
60 ether_addr_copy((u8 *)tmpaddr, eth_hdr(skb)->h_dest);
61 ether_addr_copy(eth_hdr(skb)->h_dest, eth_hdr(skb)->h_source);
62 ether_addr_copy(eth_hdr(skb)->h_source, (u8 *)tmpaddr);
63 }
64
65 return action;
66
67drop:
68 qstats_overlimit_inc(this_cpu_ptr(d->common.cpu_qstats));
69 return TC_ACT_SHOT;
70}
71
72static const struct nla_policy skbmod_policy[TCA_SKBMOD_MAX + 1] = {
73 [TCA_SKBMOD_PARMS] = { .len = sizeof(struct tc_skbmod) },
74 [TCA_SKBMOD_DMAC] = { .len = ETH_ALEN },
75 [TCA_SKBMOD_SMAC] = { .len = ETH_ALEN },
76 [TCA_SKBMOD_ETYPE] = { .type = NLA_U16 },
77};
78
79static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
80 struct nlattr *est, struct tc_action **a,
81 int ovr, int bind, bool rtnl_held,
82 struct tcf_proto *tp,
83 struct netlink_ext_ack *extack)
84{
85 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
86 struct nlattr *tb[TCA_SKBMOD_MAX + 1];
87 struct tcf_skbmod_params *p, *p_old;
88 struct tcf_chain *goto_ch = NULL;
89 struct tc_skbmod *parm;
90 struct tcf_skbmod *d;
91 bool exists = false;
92 u8 *daddr = NULL;
93 u8 *saddr = NULL;
94 u16 eth_type = 0;
95 u32 lflags = 0;
96 int ret = 0, err;
97
98 if (!nla)
99 return -EINVAL;
100
101 err = nla_parse_nested_deprecated(tb, TCA_SKBMOD_MAX, nla,
102 skbmod_policy, NULL);
103 if (err < 0)
104 return err;
105
106 if (!tb[TCA_SKBMOD_PARMS])
107 return -EINVAL;
108
109 if (tb[TCA_SKBMOD_DMAC]) {
110 daddr = nla_data(tb[TCA_SKBMOD_DMAC]);
111 lflags |= SKBMOD_F_DMAC;
112 }
113
114 if (tb[TCA_SKBMOD_SMAC]) {
115 saddr = nla_data(tb[TCA_SKBMOD_SMAC]);
116 lflags |= SKBMOD_F_SMAC;
117 }
118
119 if (tb[TCA_SKBMOD_ETYPE]) {
120 eth_type = nla_get_u16(tb[TCA_SKBMOD_ETYPE]);
121 lflags |= SKBMOD_F_ETYPE;
122 }
123
124 parm = nla_data(tb[TCA_SKBMOD_PARMS]);
125 if (parm->flags & SKBMOD_F_SWAPMAC)
126 lflags = SKBMOD_F_SWAPMAC;
127
128 err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
129 if (err < 0)
130 return err;
131 exists = err;
132 if (exists && bind)
133 return 0;
134
135 if (!lflags) {
136 if (exists)
137 tcf_idr_release(*a, bind);
138 else
139 tcf_idr_cleanup(tn, parm->index);
140 return -EINVAL;
141 }
142
143 if (!exists) {
144 ret = tcf_idr_create(tn, parm->index, est, a,
145 &act_skbmod_ops, bind, true);
146 if (ret) {
147 tcf_idr_cleanup(tn, parm->index);
148 return ret;
149 }
150
151 ret = ACT_P_CREATED;
152 } else if (!ovr) {
153 tcf_idr_release(*a, bind);
154 return -EEXIST;
155 }
156 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
157 if (err < 0)
158 goto release_idr;
159
160 d = to_skbmod(*a);
161
162 p = kzalloc(sizeof(struct tcf_skbmod_params), GFP_KERNEL);
163 if (unlikely(!p)) {
164 err = -ENOMEM;
165 goto put_chain;
166 }
167
168 p->flags = lflags;
169
170 if (ovr)
171 spin_lock_bh(&d->tcf_lock);
172
173 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
174 p_old = rcu_dereference_protected(d->skbmod_p, 1);
175
176 if (lflags & SKBMOD_F_DMAC)
177 ether_addr_copy(p->eth_dst, daddr);
178 if (lflags & SKBMOD_F_SMAC)
179 ether_addr_copy(p->eth_src, saddr);
180 if (lflags & SKBMOD_F_ETYPE)
181 p->eth_type = htons(eth_type);
182
183 rcu_assign_pointer(d->skbmod_p, p);
184 if (ovr)
185 spin_unlock_bh(&d->tcf_lock);
186
187 if (p_old)
188 kfree_rcu(p_old, rcu);
189 if (goto_ch)
190 tcf_chain_put_by_act(goto_ch);
191
192 if (ret == ACT_P_CREATED)
193 tcf_idr_insert(tn, *a);
194 return ret;
195put_chain:
196 if (goto_ch)
197 tcf_chain_put_by_act(goto_ch);
198release_idr:
199 tcf_idr_release(*a, bind);
200 return err;
201}
202
203static void tcf_skbmod_cleanup(struct tc_action *a)
204{
205 struct tcf_skbmod *d = to_skbmod(a);
206 struct tcf_skbmod_params *p;
207
208 p = rcu_dereference_protected(d->skbmod_p, 1);
209 if (p)
210 kfree_rcu(p, rcu);
211}
212
213static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a,
214 int bind, int ref)
215{
216 struct tcf_skbmod *d = to_skbmod(a);
217 unsigned char *b = skb_tail_pointer(skb);
218 struct tcf_skbmod_params *p;
219 struct tc_skbmod opt = {
220 .index = d->tcf_index,
221 .refcnt = refcount_read(&d->tcf_refcnt) - ref,
222 .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
223 };
224 struct tcf_t t;
225
226 spin_lock_bh(&d->tcf_lock);
227 opt.action = d->tcf_action;
228 p = rcu_dereference_protected(d->skbmod_p,
229 lockdep_is_held(&d->tcf_lock));
230 opt.flags = p->flags;
231 if (nla_put(skb, TCA_SKBMOD_PARMS, sizeof(opt), &opt))
232 goto nla_put_failure;
233 if ((p->flags & SKBMOD_F_DMAC) &&
234 nla_put(skb, TCA_SKBMOD_DMAC, ETH_ALEN, p->eth_dst))
235 goto nla_put_failure;
236 if ((p->flags & SKBMOD_F_SMAC) &&
237 nla_put(skb, TCA_SKBMOD_SMAC, ETH_ALEN, p->eth_src))
238 goto nla_put_failure;
239 if ((p->flags & SKBMOD_F_ETYPE) &&
240 nla_put_u16(skb, TCA_SKBMOD_ETYPE, ntohs(p->eth_type)))
241 goto nla_put_failure;
242
243 tcf_tm_dump(&t, &d->tcf_tm);
244 if (nla_put_64bit(skb, TCA_SKBMOD_TM, sizeof(t), &t, TCA_SKBMOD_PAD))
245 goto nla_put_failure;
246
247 spin_unlock_bh(&d->tcf_lock);
248 return skb->len;
249nla_put_failure:
250 spin_unlock_bh(&d->tcf_lock);
251 nlmsg_trim(skb, b);
252 return -1;
253}
254
255static int tcf_skbmod_walker(struct net *net, struct sk_buff *skb,
256 struct netlink_callback *cb, int type,
257 const struct tc_action_ops *ops,
258 struct netlink_ext_ack *extack)
259{
260 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
261
262 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
263}
264
265static int tcf_skbmod_search(struct net *net, struct tc_action **a, u32 index)
266{
267 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
268
269 return tcf_idr_search(tn, a, index);
270}
271
272static struct tc_action_ops act_skbmod_ops = {
273 .kind = "skbmod",
274 .id = TCA_ACT_SKBMOD,
275 .owner = THIS_MODULE,
276 .act = tcf_skbmod_act,
277 .dump = tcf_skbmod_dump,
278 .init = tcf_skbmod_init,
279 .cleanup = tcf_skbmod_cleanup,
280 .walk = tcf_skbmod_walker,
281 .lookup = tcf_skbmod_search,
282 .size = sizeof(struct tcf_skbmod),
283};
284
285static __net_init int skbmod_init_net(struct net *net)
286{
287 struct tc_action_net *tn = net_generic(net, skbmod_net_id);
288
289 return tc_action_net_init(tn, &act_skbmod_ops);
290}
291
292static void __net_exit skbmod_exit_net(struct list_head *net_list)
293{
294 tc_action_net_exit(net_list, skbmod_net_id);
295}
296
297static struct pernet_operations skbmod_net_ops = {
298 .init = skbmod_init_net,
299 .exit_batch = skbmod_exit_net,
300 .id = &skbmod_net_id,
301 .size = sizeof(struct tc_action_net),
302};
303
304MODULE_AUTHOR("Jamal Hadi Salim, <jhs@mojatatu.com>");
305MODULE_DESCRIPTION("SKB data mod-ing");
306MODULE_LICENSE("GPL");
307
308static int __init skbmod_init_module(void)
309{
310 return tcf_register_action(&act_skbmod_ops, &skbmod_net_ops);
311}
312
313static void __exit skbmod_cleanup_module(void)
314{
315 tcf_unregister_action(&act_skbmod_ops, &skbmod_net_ops);
316}
317
318module_init(skbmod_init_module);
319module_exit(skbmod_cleanup_module);
320
